Vacuum pump



FIG. 1 is a top, front and side perspective view of one embodiment of my design for a vacuum pump;

FIG. 2 is an enlarged detail view of area 2 circumscribed within FIG. 1;

FIG. 3 is a front view thereof;

FIG. 4 is an enlarged detail view of area 4 circumscribed within FIG. 3;

FIG. 5 is an enlarged detail view of area 5 circumscribed within FIG. 3;

FIG. 6 is a side view thereof;

FIG. 7 is an enlarged detail view of area 7 circumscribed within FIG. 6;

FIG. 8 is a rear view thereof;

FIG. 9 is another side view thereof, opposite the side view of FIG. 6;

FIG. 10 is a top view thereof; and,

FIG. 11 is a bottom view thereof.

The area shown in broken lines show environmental structure only and form no part of the claimed design. 

CLAIM The ornamental design for a vacuum pump, as shown and described. 